
var ddajaxtabssettings={}
ddajaxtabssettings.bustcachevar=1  //bust potential caching of external pages after initial request? (1=yes, 0=no)
ddajaxtabssettings.loadstatustext="<img src='http://4.bp.blogspot.com/-iM8M3gGIcaU/UKvNAjYsNKI/AAAAAAAACqI/X0JOgDMQS0Q/s320/loading.gif' /> Loading..." 

function ddajaxtabs(tabinterfaceid, contentdivid){
 this.tabinterfaceid=tabinterfaceid //ID of Tab Menu main container
 this.tabs=document.getElementById(tabinterfaceid).getElementsByTagName("a") //Get all tab links within container
 this.enabletabpersistence=true
 this.hottabspositions=[] //Array to store position of tabs that have a "rel" attr defined, relative to all tab links, within container
 this.currentTabIndex=0 //Index of currently selected hot tab (tab with sub content) within hottabspositions[] array
 this.contentdivid=contentdivid
 this.defaultHTML=""
 this.defaultIframe='<iframe frameborder="0" height="640" width="100%" scrolling="no" src="about:blank" class="tabcontentiframe"></iframe>'
 this.defaultIframe=this.defaultIframe.replace(/<iframe/i, '<iframe name="'+"_ddajaxtabsiframe-"+contentdivid+'" ')
this.revcontentids=[] //Array to store ids of arbitrary contents to expand/contact as well ("rev" attr values)
 this.selectedClassTarget="link" //keyword to indicate which target element to assign "selected" CSS class ("linkparent" or "link")
}

ddajaxtabs.connect=function(pageurl, tabinstance){
 var page_request = false
 var bustcacheparameter=""
 if (window.ActiveXObject){ //Test for support for ActiveXObject in IE first (as XMLHttpRequest in IE7 is broken)
  try {
  page_request = new ActiveXObject("Msxml2.XMLHTTP")
  } 
  catch (e){
   try{
   page_request = new ActiveXObject("Microsoft.XMLHTTP")
   }
   catch (e){}
  }
 }
 else if (window.XMLHttpRequest) // if Mozilla, Safari etc
  page_request = new XMLHttpRequest()
 else
  return false
 var ajaxfriendlyurl=pageurl.replace(/^http:\/\/[^\/]+\//i, "http://"+window.location.hostname+"/") 
 page_request.onreadystatechange=function(){ddajaxtabs.loadpage(page_request, pageurl, tabinstance)}
 if (ddajaxtabssettings.bustcachevar) //if bust caching of external page
  bustcacheparameter=(ajaxfriendlyurl.indexOf("?")!=-1)? "&"+new Date().getTime() : "?"+new Date().getTime()
 page_request.open('GET', ajaxfriendlyurl+bustcacheparameter, true)
 page_request.send(null)
}

ddajaxtabs.loadpage=function(page_request, pageurl, tabinstance){
 var divId=tabinstance.contentdivid
 document.getElementById(divId).innerHTML=ddajaxtabssettings.loadstatustext //Display "fetching page message"
 if (page_request.readyState == 4 && (page_request.status==200 || window.location.href.indexOf("http")==-1)){
  document.getElementById(divId).innerHTML=page_request.responseText
  ddajaxtabs.ajaxpageloadaction(pageurl, tabinstance)
 }
}

ddajaxtabs.ajaxpageloadaction=function(pageurl, tabinstance){
 tabinstance.onajaxpageload(pageurl) //call user customized onajaxpageload() function when an ajax page is fetched/ loaded
}

ddajaxtabs.getCookie=function(Name){ 
 var re=new RegExp(Name+"=[^;]+", "i"); //construct RE to search for target name/value pair
 if (document.cookie.match(re)) //if cookie found
  return document.cookie.match(re)[0].split("=")[1] //return its value
 return ""
}

ddajaxtabs.setCookie=function(name, value){
 document.cookie = name+"="+value+";path=/" //cookie value is domain wide (path=/)
}

ddajaxtabs.prototype={

 expandit:function(tabid_or_position){ //PUBLIC function to select a tab either by its ID or position(int) within its peers
  this.cancelautorun() //stop auto cycling of tabs (if running)
  var tabref=""
  try{
   if (typeof tabid_or_position=="string" && document.getElementById(tabid_or_position).getAttribute("rel")) //if specified tab contains "rel" attr
    tabref=document.getElementById(tabid_or_position)
   else if (parseInt(tabid_or_position)!=NaN && this.tabs[tabid_or_position].getAttribute("rel")) //if specified tab contains "rel" attr
    tabref=this.tabs[tabid_or_position]
  }
  catch(err){alert("Invalid Tab ID or position entered!")}
  if (tabref!="") //if a valid tab is found based on function parameter
   this.expandtab(tabref) //expand this tab
 },

 cycleit:function(dir, autorun){ //PUBLIC function to move foward or backwards through each hot tab (tabinstance.cycleit('foward/back') )
  if (dir=="next"){
   var currentTabIndex=(this.currentTabIndex<this.hottabspositions.length-1)? this.currentTabIndex+1 : 0
  }
  else if (dir=="prev"){
   var currentTabIndex=(this.currentTabIndex>0)? this.currentTabIndex-1 : this.hottabspositions.length-1
  }
  if (typeof autorun=="undefined") //if cycleit() is being called by user, versus autorun() function
   this.cancelautorun() //stop auto cycling of tabs (if running)
  this.expandtab(this.tabs[this.hottabspositions[currentTabIndex]])
 },

 setpersist:function(bool){ //PUBLIC function to toggle persistence feature
   this.enabletabpersistence=bool
 },

 loadajaxpage:function(pageurl){ //PUBLIC function to fetch a page via Ajax and display it within the Tab Content instance's container
  ddajaxtabs.connect(pageurl, this)
 },

 loadiframepage:function(pageurl){ //PUBLIC function to fetch a page and load it into the IFRAME of the Tab Content instance's container
  this.iframedisplay(pageurl, this.contentdivid)
 },

 setselectedClassTarget:function(objstr){ //PUBLIC function to set which target element to assign "selected" CSS class ("linkparent" or "link")
  this.selectedClassTarget=objstr || "link"
 },

 getselectedClassTarget:function(tabref){ //Returns target element to assign "selected" CSS class to
  return (this.selectedClassTarget==("linkparent".toLowerCase()))? tabref.parentNode : tabref
 },

 urlparamselect:function(tabinterfaceid){
  var result=window.location.search.match(new RegExp(tabinterfaceid+"=(\\d+)", "i")) //check for "?tabinterfaceid=2" in URL
  return (result==null)? null : parseInt(RegExp.$1) //returns null or index, where index (int) is the selected tab's index
 },

 onajaxpageload:function(pageurl){ //PUBLIC Event handler that can invoke custom code whenever an Ajax page has been fetched and displayed
  //do nothing by default
 },

 expandtab:function(tabref){
  var relattrvalue=tabref.getAttribute("rel")
  //Get "rev" attr as a string of IDs in the format ",john,george,trey,etc," to easy searching through
  var associatedrevids=(tabref.getAttribute("rev"))? ","+tabref.getAttribute("rev").replace(/\s+/, "")+"," : ""
  if (relattrvalue=="#default")
   document.getElementById(this.contentdivid).innerHTML=this.defaultHTML
  else if (relattrvalue=="#iframe")
   this.iframedisplay(tabref.getAttribute("href"), this.contentdivid)
  else
   ddajaxtabs.connect(tabref.getAttribute("href"), this)
  this.expandrevcontent(associatedrevids)
  for (var i=0; i<this.tabs.length; i++){ //Loop through all tabs, and assign only the selected tab the CSS class "selected"
   this.getselectedClassTarget(this.tabs[i]).className=(this.tabs[i].getAttribute("href")==tabref.getAttribute("href"))? "selected" : ""
  }
  if (this.enabletabpersistence) //if persistence enabled, save selected tab position(int) relative to its peers
   ddajaxtabs.setCookie(this.tabinterfaceid, tabref.tabposition)
  this.setcurrenttabindex(tabref.tabposition) //remember position of selected tab within hottabspositions[] array
 },

 iframedisplay:function(pageurl, contentdivid){
  if (typeof window.frames["_ddajaxtabsiframe-"+contentdivid]!="undefined"){
   try{delete window.frames["_ddajaxtabsiframe-"+contentdivid]} //delete iframe within Tab content container if it exists (due to bug in Firefox)
   catch(err){}
  }
  document.getElementById(contentdivid).innerHTML=this.defaultIframe
  window.frames["_ddajaxtabsiframe-"+contentdivid].location.replace(pageurl) //load desired page into iframe
 },


 expandrevcontent:function(associatedrevids){
  var allrevids=this.revcontentids
  for (var i=0; i<allrevids.length; i++){ //Loop through rev attributes for all tabs in this tab interface
   //if any values stored within associatedrevids matches one within allrevids, expand that DIV, otherwise, contract it
   document.getElementById(allrevids[i]).style.display=(associatedrevids.indexOf(","+allrevids[i]+",")!=-1)? "block" : "none"
  }
 },

 setcurrenttabindex:function(tabposition){ //store current position of tab (within hottabspositions[] array)
  for (var i=0; i<this.hottabspositions.length; i++){
   if (tabposition==this.hottabspositions[i]){
    this.currentTabIndex=i
    break
   }
  }
 },

 autorun:function(){ //function to auto cycle through and select tabs based on a set interval
  this.cycleit('next', true)
 },

 cancelautorun:function(){
  if (typeof this.autoruntimer!="undefined")
   clearInterval(this.autoruntimer)
 },

 init:function(automodeperiod){
  var persistedtab=ddajaxtabs.getCookie(this.tabinterfaceid) //get position of persisted tab (applicable if persistence is enabled)
  var selectedtab=-1 //Currently selected tab index (-1 meaning none)
  var selectedtabfromurl=this.urlparamselect(this.tabinterfaceid) //returns null or index from: tabcontent.htm?tabinterfaceid=index
  this.automodeperiod=automodeperiod || 0
  this.defaultHTML=document.getElementById(this.contentdivid).innerHTML
  for (var i=0; i<this.tabs.length; i++){
   this.tabs[i].tabposition=i //remember position of tab relative to its peers
   if (this.tabs[i].getAttribute("rel")){
    var tabinstance=this
    this.hottabspositions[this.hottabspositions.length]=i //store position of "hot" tab ("rel" attr defined) relative to its peers
    this.tabs[i].onclick=function(){
     tabinstance.expandtab(this)
     tabinstance.cancelautorun() //stop auto cycling of tabs (if running)
     return false
    }
    if (this.tabs[i].getAttribute("rev")){ //if "rev" attr defined, store each value within "rev" as an array element
     this.revcontentids=this.revcontentids.concat(this.tabs[i].getAttribute("rev").split(/\s*,\s*/))
    }
    if (selectedtabfromurl==i || this.enabletabpersistence && selectedtab==-1 && parseInt(persistedtab)==i || !this.enabletabpersistence && selectedtab==-1 && this.getselectedClassTarget(this.tabs[i]).className=="selected"){
     selectedtab=i //Selected tab index, if found
    }
   }
  } //END for loop
  if (selectedtab!=-1) //if a valid default selected tab index is found
   this.expandtab(this.tabs[selectedtab]) //expand selected tab (either from URL parameter, persistent feature, or class="selected" class)
  else //if no valid default selected index found
   this.expandtab(this.tabs[this.hottabspositions[0]]) //Just select first tab that contains a "rel" attr
  if (parseInt(this.automodeperiod)>500 && this.hottabspositions.length>1){
   this.autoruntimer=setInterval(function(){tabinstance.autorun()}, this.automodeperiod)
  }
 } //END int() function

}